Apparatus for process of drying oil



Oct. 4, 1949.

APPARATUS FOR PROCESS OF DRYING OIL Filed Oct. 15, 1945 B. CLAYTON Patented Oct. 4, 1949 l 2,483,623 APPARATUS FOB PROCESS F DRYING OIL Benjamin Clayton, Hons mesne assignments, Houston, Tex., doing business as Refining,

incorporated ton, Tex, assigner, by to Beni amin Clayton,

Appucaaon ombu- 15, 194s, serai No. 505.429 s calms. (c1. 21e- 41) This invention relates to a process of drying oil and more particularly .to a process of removing small quantities of water contained in said oil.

The invention has particular utility in removing the small quantities of water which persist in glyceride oils after these oils have been treated with water or aqueous solutions in refining operations or water washing operations. The refining of glyceride oils such as animal or vegetable oils usually involves mixing the oil with aqueous alkali solutions either before or after preliminary operations involving the employment of aqueous solutions for removing gums. The alkali solutions from soapstocks which are separated from the oil usually by centrifugal separation to produce a refined oil containing small amounts of moisture, soap, etc., which amount of moisture is usually in the neighborhood of a few tenths of 1%. To remove residual alkali or soap it is usually desirable to wash the oilby intimately mixing water therewith and then separating the bulk `of the water from the oil byv centrifugal separation so as to remove the majority of the impurities therefrom. In this case also a small amount of residual water is left in theoil, usually in the neighborhood of a yfew tenths of 1%. A portion of this water either after the refining Astep or a water washing step appears to be present in a particularly persistent emulsion or suspension referred to in the art as "hydrosol" which is extremely difheult to remove from the oil and which includes water and air or other gas in finely dispersed form. This water cannot be effectively removed by filtration and alsopersistently holds impurities such as alkali or soap dissolved therein in the oil during a filtering operation.

By vaporizing the water out of the oil the oil can be substantially completely dried and any impurities insoluble in the oil and held in the finely divided water are released so that they may be effectively filtered from the oil to produce a bright, high quality refined oil. Such drying operations have heretofore involved the step of heating the entire body of oil to a relatively high temperature and usually include flashing the same into a vacuum or'alternatively have involved the heating of `large bodies of the oil in vacuum for considerable periods of time at high temperatures.

In accordance with the present invention it is possible to selectively heat the water contained in the oil so as to vaporize the same and withdraw it from the oil without heating the entire body of oil to a high temperature. The' oil containing the undesired water may be advantageously treated in a continuous manner in thin films preferably under vacuum conditions so that the vapor generated by evaporation of the water is rapidly and efficiently removed without materially raising the average temperature of the body of the oil. This not only results in a maior saving of power but also avoids the known deleterious effect of high temperatures upon such oils. The process of the present invention is preferably applied to the oil after a water 'washing step as such a water washing step does remove a substantial quantity of undesirable impurities such as soap and residual alkali and the resulting oil may be easily clarified with a minimum of treatment although the drying step of the present invention may be applied to the oil as it comes from the alkali refining step and residual impurities such as soap or alkali thereafter easily filtered from the oil.

In carrying out the present invention, a layer of the oil is subjected to a high frequency alternating field in a zone providing for free escape of l water vapor from the oil and preferably under vacuum conditions to assist in withdrawal of vapor, from the oil.y The treatment of the oil under vacuum markedly reduces the amount of electric power necessary for the drying operation. Such e an operation not only rapidly and efliclently dries the oil with the expenditure of a much smaller amount of heat thanis required in previous drying operations, but also markedly improves the odor of the oil, apparently by withdrawal of volatile odcrous materials from the oil. Although the process -of the present invention has particular utility in drying glyceride oils, it is also applicable to the drying of substantially any liquid, for example hydrocarbon oils, which contains small amounts of water and which is substantially immiscible with water and has electrical characteristics enabling selective heating of the water.

It is therefore an object of the present invention to provide an improved process of drying oils containing small amounts of water dissolved or suspended therein. Another object of the invention is to provide a process of treating oils containing small amounts of water to remove the water in which the oil is subjected to a high frequency alternating field to selectively heat the contained water under conditions enabling withdrawal of the vapors generated by the selective heating operation.

A further object of the invention is to provide an improved process of drying a liquid which is substantially immiscible with water but which contains a small amount of moisture dissolved or suspended therein and which has electrical characteristics enabling selective heating of the water.

A still further object of the invention to provide an apparatus for continuously subiecting a liquid to a high frequency alternating eld under conditions providing for the removal of vapor from said liquid.

Other objects and advantages of the invention will appear in the following description of preferred embodiments of the invention given in connection with the attached drawing of which Fig. 1 shows an apparatus for subjecting a thin film of liquid to a high frequency electric magnetic field; and

Fig. 2 is a view similar to Fig. 1, showing an apparatus for subjecting a flowing film of a liquid to a high frequency electrostatic field.

Referring to Fig. 1 the apparatus therein disclosed includes a closed chamber 'I0 constructed of insulating material into which a pipe of insulating material I I delivers a liquid to a spreader member i2, the liquid entering the interior of the spreader member I2 through apertures I3 in the pipe I I. The spreader member I2 is also constructed of insulating material and has its lower periphery i4 positioned adjacent the upper conical end of a central member I6 so as to provide a small gap I1 for distributing the liquid over the surface of the member I6 so that the liquid material flows down the outer surface of the member I6 in a thin lm. The body of central member I6 is preferably cylindrical in shape and is also constructed of insulating material. This member may be supported on the lower portion la of the casing I0 and may be provided with lower apertures or notches i9 so that the treated liquid may enter the interior of the member I6 and be discharged through an extension 20 of the casing Il) also of insulating material.

The upper end of the centraal member I6 may project into the lower end of the pipe II to hold the member I6 centered with respect to the spreader member I2 and the casing Il and the pipe Ii may be supported and held centrally of the casing I0 by means of a cap member 22 for the casing I Il, the cap member also being made of insulating material. The casing I0 may also be provided with a pipe connection 23, also of insulating material, for withdrawing vapors from the chamber i0. The various pipes II, 2| and 23 may be connected to the metal pipes 24, 26 and 21, respectively, by any suitable connectors, such as the connectors 23. A coil 23 having a few turns surrounding the casing I Il and connected across a high frequency generator 3i may be em-V ployed to produce a high frequency electromagnetic field in the casing I 0 so that the lm of liquid flowing down over the central member I6 is subjected to such field. The coil 29 preferably comprises a pipe of conducting material such as copper and also preferably has its ends connected to pipes 32 and 33 of insulating material to provide for the flow of a liquid cooling medium through the coil 29.

The apparatus of Fig. 2 provides for treating a thin film of liquid with a high frequency electrostatic eld and includes a casing 34 of conducting material, such as metal, surrounding a central member 36 also of conducting material, such as metal. The central member 36 may be made in two portions 31 and 36 connected by an internal member 33 for purposes of assembly and is supported at its lower end by a pipe 4I provided with a flange 42. The upper end of the central member 36 may be likewise supported by a pipe 43-carrying a spreader member 44 having its lower periphery adjacent the upper conical 4 end of the central member 33. The pipe 43 may be provided with a ange 46 connecting the pipe 43 to a liquid inlet pipe 41 and to a vapor dome member 48 surrounding the pipe 43 and provided at its lower end with a flange 43. The casing 34 may have its ends connected in vapor-tight rellation with bells 5| and 52 of insulating material, the upper end of the bell 5| being connected to `the flange 49 of the vapor dome 46 and the lower end of the bell 52 being connected to the flange 42 of the discharge pipe 4I. The discharge pipe 4| may be provided with apertures 53 above the flange 42 so that treated liquid may be discharged from the device through the pipe 4I.

It will be apparent that liquid may enter through the pipe 41 and be caused to flow down over the central member 36 by the spreader member 44 through a treating space between the central member 36 and the casing 34 and be discharged from the treating chamber through the pipe 4I. Also, vapor generated in the treating chamber may be withdrawn from said chamber through a pipe 54 connected to the vapor dome 43. If desired the entire treating chamber may be surrounded by a shielding casing 56 and all of the conducting members of the device may be maintained at ground potential except the casing 34 which constitutes the high voltage electrode, the central member 31 constituting the other electrode. An electrostatic field may be produced between the member 36 and casing 34 by means of a high frequency generator 51 having one terminal connected to the casing 34 through the central conductor 34 of a coaxial line having an external conductor I3 connected to the shielding casing 53 and thus to the central member 36 through the metallic pipes 4I and 43.

'I'he preferred operation in accordance with the present invention is that carried out in Fig. 2 in which the oil or other liquid to be dried is sub- Jected to a high frequency electrostatic neld. In general, the moisture contained in the oil has a higher power factor than the oil so that an electrostatic field selectively heats this moisture and causes the same to vaporize before the average temperature of the main body of the iilm of oil has its temperature materially increased. This is particularly true if the oil is treated in a thin nlm and is subjected to vacuum conditions during the heating operation. By treating the oil in a layer which does not nil the space between the central member 36 and the casing 34, a vacuum can be produced in the entire treating chamber by connecting the same to any suitable condensing and vacuum system (not shown) through the pipe B4. Any emulsion of water and oil or complex emulsion of water, air and oil is rapidly broken, the water evaporated and the resulting vapor and any air or other gas present is rapidly withdrawn from the oil. without much increase in temperature of the main body of the oil as the amount of water being evaporated in accordance with the present invention is an extremely small part of the material being treated. 'I'hls is in contrast to prior drying operations in which the entire body of the oil was heated to relatively high temperatures, for example, temperatures approaching the boiling point of water.

Any suitable type oi' high frequency generator capable of producing a substantial power output at high frequency may be employed and such generators are known and need not be specifically described. The frequency employed for treatment o! liquids in accordance with the pres- This is accomplished ent invention, with an electrostatic field. will ordinarily range between land 50 megacycles depending upon the nature of the material being treated and this frequency will usually fall between and 30 megacycles. In general, the higher frequency employed the lower the voltage necessary for effective treatment but an optimum frequency producing maximum effect drying for a given power input will .usually be found for each material being treated depending upon'the amount of water present and the nature of the liquid containing the water. The process of Fig. 2 is applicable to almost every type of liquid which is substantially immiscible with water which has a lower power factor than water and which contains a small amount of water, irrespective of whether the water contains impurities rendering the water conductive.

The apparatus of Fig. 1 is generally applicable to liquids substantially immiscible with water which containa small amount of water containing sufficient electrolytes therein to render the water conducting. Under these conditions the electromagnetic field selectively heats the water so that it is vaporized and withdrawn along with any other gas or air present, substantially as described with respect to Fig. 2. Again, any known or suitable high frequency generator may be employed which will produce high currents at high frequency. In general the with Fig. 1 are lower than those employed in the process of Fig. 2 and will generally range from about kilocycles up to 1000 kilocycles, frequencies intermediate this range, namely 100` to 500 klocycles, being those generally employed. Again, the exact frequency will depend upon the nature of the material being treated. The range of frequencies contemplated by the present invention is, therefore, substantially coextensive with the range of radio frequencies. In both of the processes of Fig. l and Fig. 2 it is desirable to treat the liquid in thin films in order to give opportunity for vapors and gases to escape from the liquid and in the case of magnetic fields to enable penetration of the field into the liquid having the conducting material therein.

Although heating by high frequency alternating fields is generally considered to be a relatively expensive operation, as high frequency generators are not in able energy is lost in the form of heat which is not usable in the treating operation, the drying of oils containing small amounts of water, i. e., not more than approximately 2% or 3% and usually a few tenths of 1% can be economically carried out since the average temperature of the material is usually not materially raised and substantially all of the heat generated by the eld is employed in heating only the water. While the present invention was developed in connection with the drying of animal and vegetable oils, it is apparent that it is in general applicable wherever small amounts of liquid are present in a substantially immiscible liquid and where the liquid present in minor proportion has greater conductivty 0r a higher power factor than the other liquid.

This application is a continuation in part of my copending application Serial No. 496,213, filed July 26, 1943, now abandoned.

While I have disclosed the preferred embodiments of my invention it is understood that the details thereof can be varied within the scope of the following claims.

frequencies employed general efficient devices and consider- I claim:A 4

1. Apparatus for vaporizin'g water from another liquid in which a small amount of said water is dispersed, which apparatus comprises, a. vertically extending enclosing casing forming a closed chamber, said chamber having therein a vertically extending surface, a spreader member adjacent the upper portion of said chamber providing an aperture adjacent the upper portion of said ,surface for spreading a thin film of said liquid upon said surface Lso that said liquid flows down said surface as a nlm, said surface being spaced from adjacent surfaces in said chamber a distancegreater than the thickness of said film to provide a vaporizing space at the free surface of said film for liberation of water vapor, means including a radio frequency generator for producing a radio frequency alternating field in said liquid of sufilcient intensity to vaporize said water, means for delivering said liquid to said spreader member, means for discharging water vapor from said chamber and means for discharging the dried liquid from the lower portion of said chamber at a rate sufficient to maintain said vaporizing space free from liquid.

2. Apparatus for vaporizing water from another liquid in which a small amount of said water is dispersed, which apparatus comprises, a vertically extending enclosing casing forming a closed chamber, said chamber having therein a vertically extending surface. a spreader member adjacent the upper portion of said chamber having a spreader portion adjacent the upper portion of said surface providing a gap between said surface and said spreader portion for spreading a thin film of said liquid upon said surface so that said liquid flows down said surface as a film, said surface being spaced from adjacent surfaces in said chamber a distance greater than the thickness of said film to provide a vaporizing space at the free surface of said nim for liberation of water vapor, means including a radio frequency generator for producing a radio frequency alternating field in said liquid of sufficient intensity to vaporize said water, means for delivering said' liquid to said spreader member, means for discharging water vapor from said chamber and means for discharging the dried liquid from the lower portion of said chamber at a rate suflicient to maintain said vaporizing space free from liquid.

3. Apparatus for vaporizing water from another liquid in which a small amount of said water is dispersed, which apparatus comprises, a vertically extending central member, a vertically extending casing surrounding said central member to form a closed chamber, said central member having a vertically extending surface in said chamber, a spreader member in the upper portion of said chamber having a spreader portion adjacent the upper portion of said surface providing a gap between said surface and said spreader portion for spreading a film of said liquid on said surface so that said liquid flows down said surface as a nlm, said casing being spaced from said central member a distance greater than the thickness of said film to provide a vaporizing space at the free surface of said film for liberation of water vapor, means including a radio frequency generator for producing a. radio frequency alternating iield in said liquid of suilicient intensity to vaporize said water, means for delivering said liquid to said spreader member, means for discharging water 7 .a vapor from said chamber and means for di Number Name Date harging the dried liquid from the lower portion 1,900,573 McArthur Har. '1, 1938 of said chamber at'a rate sll'lcient t0 maintain 1,978,509 Roberts Oct. 30, 1934 said vaporizing space iree from liquid. 2,087,480 Pitman July 2o, 1937 BENJAMIN CLAYTON. 5 2,110,899 Woeln Mar. 15, 1938 2,120,932 Dillon June 14, 1038 REFERENCES CITED 2,163,898 van der Lande .nine 27, 1930 The following references are of record in the 1335552 Biel'wilth M18- 3. 1943 file of this patent: 2,390,572 Brabander Dec. 11, 1945 7 UNITED STATES PATENTS lo FOREIGN PA'IENTS Number Name Due Number COW-'Airy Dok 500,520 Wetmore June 27, 1003 690,342 France June 1s, 1930 1,358,431 Field NOV. 9, 1920 1,597,476 Page 11113.24, me 1s 

